Vibration reducing link for vibrating screed

ABSTRACT

A vibrating screed for surfacing concrete includes a surfacing blade, a vibration-causing assembly, a steering assembly with a handle assembly and a grip member in communication with the hand assembly. A vibration reducing link is disposed between the grip member and the handle assembly so that when the vibration-causing assembly imparts a vibratory motion to the blade and the handle assembly, the vibration reducing link dampens the vibratory motion transmitted between the handle assembly and the grip member.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority, under 35 U.S.C. § 119(e), on U.S.provisional patent application serial No. 61/118,033, filed on Nov. 26,2008, which is incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a vibration dampening handlebar link.More specifically, the present invention is concerned with a vibrationreducing link for vibrating screed.

BACKGROUND OF THE INVENTION

Known in the art, there are vibrating screeds including, for instance,an elongated blade extending horizontally and transversally at lowerends of a pair of handles adapted to be hand held and operated fordisplacing the screed over a concrete surface. A motor is provided abovethe blade and between the handles and has its shaft extending verticallydownwards from the motor to the blade and is connected thereat suchthat, with a counterweight or a cam-like arrangement, it impartsoscillatory movement to the blade of high frequency but low amplitude.

Generally, such devices are guided and controlled by a pair ofhandlebars to be gripped by an operator to permit easy and constantcorrection of the level of the concrete with minimum effort. Forexample, U.S. Pat. No. 6,296,467 (Rouillard) discloses a handlebar withtextured rubber grip members attached thereto. Furthermore, the screedhas adjustable handles including a main elongated handle member. Eachhandle has a first element mounted to a proximal end of the main handlemember. The handle has second and third elements capable of relativerotatable displacement and capable of being secured in a desiredrelative position thereof with a grip member being mounted to the thirdelement such that the grip member may be swiveled at least partly aroundan axis of the second element.

However, the operation of such devices usually occurs over many hoursduring which period vibrations from the oscillatory movement of theblade will be transferred to the operator through the handles meansleading to increased operator fatigue.

While the prior art teaches of vibration isolators which act to reducethe vibration produced by a vibration exciter mechanism, such vibrationreducing isolators are located near the vibration exciter mechanismitself and away from the operator handles.

The Applicant has discovered that even with such vibrating reducingisolators located near the vibration exciter mechanism, there are stillsubstantial remaining oscillatory movements transferred to the operator.There is therefore a need for a solution to this problem of vibrationsfelt by the user when grasping handlebar grip members of vibratingscreed.

SUMMARY OF THE INVENTION

More specifically, in accordance with the present invention, there isprovided vibrating screed comprising:

-   -   a surfacing blade;    -   a vibration-causing assembly in communication with the surfacing        blade;    -   a steering assembly in communication with the surfacing blade,        the steering assembly comprising a handle assembly;    -   a grip member in communication with the handle assembly; and    -   a vibration reducing link disposed between the grip member and        the handle assembly;        wherein when the vibration-causing assembly imparts a vibratory        motion to the blade and the handle assembly, the vibration        reducing link dampens the vibratory motion transmitted between        the handle assembly and the grip member.

Preferably, the reducing link comprises: a first member in communicationwith the handle assembly; a vibration reducing coupling disposedcircumferentially about the first member; a second member incommunication with the grip, the second member receiving the vibrationreducing coupling and the first tubular member; and a clamp for securingthe first tubular members and the vibration reducing coupling within thesecond tubular members when received therein; wherein the vibrationreducing coupling dampens vibration transmitted between the first andsecond members.

Preferably, the vibration reducing coupling is disposedcircumferentially within the second member, the first member receivedwithin the vibration reducing coupling and the second member.

Preferably, the first member and the vibration reducing coupling arerotatable within the second member.

Preferably, the vibration reducing coupling has a non-elastomeric layerdisposed circumferentially about the vibration reducing coupling.

Preferably, the vibration reducing link includes a coupling made ofelastomeric material such as vulcanized rubber to couple handlebarmembers in order to dampen vibration and shock.

Preferably, the first member in substantially perpendicular incommunication to the handle assembly, the second member is substantiallyperpendicular in communication to the first member.

Preferably, the clamp is circumferentially disposed about the secondmember.

Advantageously, compared to prior art screed, the present inventionlocalizes vibration isolators closer to the handles such that theremaining vibrations not suppressed by the isolators located closer tothe vibration exciter mechanisms are further and substantially reduced.

Another advantage of the present invention over the prior art involvesthe capability of easily retrofitting the vibration reducing link to thehandle assemblies of existing screeds.

Other objects, advantages and features of the present invention willbecome more apparent upon reading of the following non-restrictivedescription of specific embodiments thereof, given by way of exampleonly with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the appended drawings:

FIG. 1 is a perspective view of a handlebar assembly for vibratingscreed incorporating a vibration reducing link used to couple handlebarassembly elements;

FIG. 2 is a perspective view of a vibration reducing link for vibratingscreed;

FIG. 3 is a cross-sectional view of the vibration reducing link of FIG.2;

FIG. 4 is a longitudinal sectional view of the invention in FIG. 1wherein the section plane is indicated by the arrows A-A of FIG. 3;

FIG. 5 is a perspective view of a handlebar element for vibratingscreed;

FIG. 6 is a perspective view of a handlebar assembly for vibratingscreed demonstrating the relative rotational and longitudinal motions ofhandlebar elements.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present invention is illustrated in further detail by the followingnon-limiting example. FIG. 1 illustrates a vibration reducing linkassembly for a vibrating screed handlebar means 10 comprising a firstelement 12, a second element 13 and a third element 14, the secondelement 13 and third element 14 capable of relative rotatabledisplacement and capable of being secured in a desired relative positionby clamping means 11. A vibration reducing assembly 15 (See FIG. 2)according to a preferred embodiment of the present invention dampensvibrations which propagate between coupled second element 13 and thirdelements 14.

Referring to FIG. 2, the vibration reducing assembly 15 is comprised ofa vulcanized rubber tubular coupling 16 linking a handlebar element 17of second element 13 to a tubular element 18. Vibrations emanating fromhandlebar element 17 are reduced as they propagate outwardly through thevulcanized rubber tubular coupling 16 to tubular element 18.

Now referring to FIG. 3, the vibration reducing assembly 15, having avulcanized rubber tubular coupling 16 enclosed by a tubular element 18and used to link the second element 13 to the third element 14, isreadily visible. As is apparent from this figure, tubular element 18 isisolated from vibrations propagating from handlebar element 17 by avulcanized rubber tubular coupling 16.

FIG. 4 is a longitudinal sectional view of the invention in FIG. 1wherein the section plane is indicated by the arrows A-A of FIG. 3. Fromthis figure, the configuration of the vibration reducing link isapparent. Vibrations propagating from handlebar element 17 to tubularelement 18 are reduced by a vulcanized tubular coupling 16.

FIG. 5 is a perspective view of the third element 14 of a vibrationreducing link assembly for vibrating screed handlebar means 10. Secondelement 13 and third element 14 are linked together by inserting thevibration reducing assembly 15 into space 19 of third element 14 andcompressing them together by clamping means 11.

FIG. 6 is a perspective view of third element 14 of a vibration reducinglink assembly for vibrating screed handlebar means 10 capable ofrelative rotatable displacement and capable of being secured in adesired relative position to second element 13. The vibration reducingassembly 15 engages space 19 (See FIG. 5) along the longitudinal axis21. Once engaged, third element 14 is rotatably displaceable about therotational axis 20 and secured to vibration reducing assembly 15 inspace 19 by clamping means 11.

In a preferred embodiment of the preferred invention, the use avibration reducing link as part of screed's handle assembly hasdemonstrated a substantial reduction in the remaining vibrationstransmitted to the upper sections of the handle assembly. The reductionin vibration is as much as 80% when compared to vibration experience inthe handle assemblies of the prior art which do not have additionalvibration isolators.

Although the present invention has been described hereinabove by way ofspecific embodiments thereof, it can be modified, without departing fromthe spirit and nature of the subject invention. For example, such avibration reducing link described herein could be used whenevervibration dampening is needed for other construction equipment such aspower trowels, concrete saws, and hand held or walk behind dirt andasphalt compactors utilizing handlebar assemblies. Furthermore,applications for such a vibration reducing grip may also include anysituation where a vibrating handlebar needs to be grasped by a user suchas is the case, for instance, for power tools, motorcycles, bicycles,and lawnmowers.

1. A vibrating screed comprising: a surfacing blade; a vibration-causingassembly in communication with said surfacing blade; a steering assemblyin communication with said surfacing blade, said steering assemblycomprising a handle assembly; a grip member in communication with saidhandle assembly; and a vibration reducing link disposed between saidgrip member and said handle assembly; wherein when saidvibration-causing assembly imparts a vibratory motion to said blade andsaid handle assembly, said vibration reducing link dampens saidvibratory motion transmitted between said handle assembly and said gripmember.
 2. The vibrating screed according to claim 1, wherein saidvibration reducing link comprises: a first member in communication withsaid handle assembly; a vibration reducing coupling disposedcircumferentially about said first member; a second member incommunication with said grip, said second member receiving saidvibration reducing coupling and said first tubular member; and a clampfor securing said first tubular members and said vibration reducingcoupling within said second tubular members when received therein;wherein said vibration reducing coupling dampens vibration transmittedbetween said first and second members.
 3. The vibrating screed accordingto claim 2, wherein said vibration reducing coupling is disposedcircumferentially within said second member, said first member receivedwithin said vibration reducing coupling and said second member.
 4. Thevibrating screed according to claim 2, wherein said first and secondmembers are tubular.
 5. The vibrating screed according to claim 2,wherein said first member and said vibration reducing coupling arerotatable within said second member.
 6. The vibrating screed accordingto claim 3, wherein said first member is rotatable within said vibrationreducing coupling and said second member.
 7. The vibrating screedaccording to claim 2, wherein said vibration reducing coupling has anon-elastomeric layer disposed circumferentially about said vibrationreducing coupling.
 8. The vibrating screed according to claim 3, whereinsaid vibration reducing coupling has a non-elastomeric layer disposedcircumferentially about said vibration reducing coupling.
 9. Thevibrating screed according to claim 2, wherein said vibration reducingcoupling is made of an elastomeric material.
 10. The vibrating screedaccording to claim 9, wherein said elastomeric material is rubber. 11.The vibrating screed according to claim 2, wherein said first member insubstantially perpendicular in communication to said handle assembly,said second member is substantially perpendicular in communication tosaid first member;
 12. The vibrating screed according to claim 2,wherein said clamp is circumferentially disposed about the secondmember.